COLLOQUIUM: 'The Physics of Can and Can’t': from the universal computer to the universal constructor

06 February 2020
Speaker: Chiara Marletto, University of Oxford
Abstract:
The theory of the universal quantum computer has brought us rapid technologicaldevelopments, together with remarkable improvements in how we understandquantum theory. There are, however, reasons to believe that quantum theory mayultimately have to be modified into a new theory: for instance, it will have tobe merged with general relativity, to incorporate gravity; and some claim thatit may be impossible to have quantum effects beyond a certain macroscopicscale. So what lies ahead of quantum theory, and of the universal quantumcomputer? To shed some light into these questions, we need a shift of logic inthe way things are explained. Specifically, one can adopt the approach wherethe basic assumptions are general principles about possible/impossibletransformations, rather than dynamical laws and initial conditions. Thisapproach is called constructor theory. I will describe its application to a handfulof interconnected problems, within information theory, thermodynamics, and evenquantum gravity. This ‘Physics of Can and Can’t' may be the first step towardsthe ultimate generalisation of the universal quantum computer, which vonNeumann called the 'universal constructor’.

[destructorextreme]

To Chiara Marletto > "if the universe is a single substance which self differentiates; then the principles which allow that behavior would yield the true grand theory of construction. From this we could design technology which alters space time as we see it.

[Nightshift]

Is a universal constructor (like in Deus Ex) through nanotechnology even possible to make & if so how close do you think we are to making one?

[Evan]

41:00 is eta the angle the system has gone around the circle of reservoir qubits?

[Evan]

53:00 is cool, asking what happens to the born rule if you vary constructor-theoretic principles of information

[alvarofernandez]

This reminds me of the Buckingham Pi theorem, which you may use to reduce the set of possible dynamic *equations* which may result from an experiment, by requiring dimensional consistency.

With constrctor theory, we are requiring that infinite precision be possible; else the candidate dynamic law is impossible. Hopefully im not completely off base...

[Evan]

What parts of quantum theory do superinformation media not have to obey? When I read the CT Info paper they were able to derive a lot of quantum properties from their defn of superinformation.

[karanchanaya]

Quantum computer sounds Amazing Chiara. Goodluck

[GrahamBessellieu]

Universal Constructor: an object that has within its repertoire all physically possible transformations (not just computations).

[rv]

I have a hunch that this theory will have more interesting applications to philosophy/epistemology than specifically to physics

[martinbiehl]

18:41 How do I know whether a theory allows for a definition of an energy? What is the criterion? What is the general notion of energy used here? Is there an example of an energy definition in system without specified dynamics?

[En_theo]

@38:40 Why does she consider that the machine Y can't cool down by using the energy of the weight ? Just use a pump that will decompress a gas and it will cool down. I'm not sure I got her point there.

[waltertanner]

Should this universal computer be an implementation of a Turing Machine?

[KaliFissure]

Stephen @Wolfram has created exactly this. A way of developing a universal Turing machine so that one could clip away rulial (dimension of computational rules) space until we find our universe by constraint.

All conservation though comes from a simple principle. The universe is of a piece. It is a single unit and so only internal form can be modified

[zephirinjeff]

It is possible to understand, the beginning of human existence self of consciousness; if, we decided to go back at the primordial of the first iota internet user.

[araneascience]

I think that the QUNIVAC paper from David Ritz Filkestein is very similar to the focus of this theory, would be great if someone merge both of them.

[sam]

When we are constrained via "known" physics and Quantum etc, how can anything new be uncovered... ? How about stepping beyond the known... then work out why it works the way it does...? Often the narrative creates the result... so drop the narrative and allow dreams in the still of the night to foster new ideas... (just saying)…

[warrenberkholtz]

Can someone smarter than I on modern physics, comment: - would this Constructor Theory correlate to better modeling of matters related to Entanglement, Network Effects and Metcalf's Law ?

[audiodead]

Not sure I am fully understanding what Chiara is proposing.

I can sort of see how you might try to predict the limits of the future development of a technology using it. e.g. travelling faster than the speed of light is impossible. Therefore interstellar travel is a non-starter (alpha centauri if 4 light years away).

I wonder if one can use it to answer questions like: Is it possible to simulate the entire universe inside a (universal quantum) computer?

Is that what this is about?

[johnnywilliams]

Im pretty sure Wolframs new science gave me a different idea of what a universal computer was

[NYM]

I love that woman... ❤️❤️❤️ Multidimensionaly!!🌹